1. Field of Invention
The invention relates to a method for the parametric production of a drilled hole in a component, in particular for the parametric production of a drilled cooling hole in a component of a gas or steam turbine, preferably in a blade of a gas or steam turbine. Furthermore, the invention relates to a drilling device, in particular for carrying out the method, and to a component in which one or more drilled holes are introduced according to the method.
2. Description Of Related Art
To achieve high levels of efficiency with at the same time a high specific output, gas turbines are today operated with a very high turbine inlet temperature. The temperature of the hot fluid flow emerging from the combustion chamber and entering the turbine often exceeds the permissible material temperature of the turbine blading. To make it possible nevertheless for the gas turbine to be operated reliably and with a long lifetime, it is necessary to cool the blades of the turbine, and often also the blade roots and the housing wall. A very effective cooling method here is that of film cooling, in which it is attempted to cover the component that is to be cooled with a film of cooling fluid at the locations to be cooled and in this way shield them from the hot gas. To apply the film of cooling fluid, cooling fluid, for example cooling air, which has been diverted from a preceding compressor stage, is usually conducted by means of cooling ducts into the interior of the blade that is to be cooled, which is hollow on the inside, and from there via a multiplicity of drilled cooling holes to the outer side of the blade. The cooling fluid emerging from the drilled cooling holes is deflected and made to expand as it leaves the drilled cooling holes by the flow of hot gas flowing over the blade, in such a way that it forms a cooling film along the wall of the blade. The cooling film prevents hot gas from coming into contact directly with the blade.